Semiconductor laser device

Abstract

A semiconductor laser device including an external resonator including: emitters of a semiconductor laser which output a plurality of beams having different wavelengths; a combining optical system which spatially overlaps the plurality of beams output from the semiconductor laser; a wavelength dispersive element which overlaps the overlapped plurality of beams into a single beam by wavelength dispersion; and a partial reflecting mirror which reflects a portion of the single beam and returns same to the wavelength dispersive element, wherein when the width of the wavelength dispersive element in a direction in which the single beam is separated into a plurality of beams by wavelength dispersion is taken as a wavelength dispersive element width, and when the beam upon establishment of normal oscillation is taken as a normal oscillation beam, the wavelength dispersive element width is the same size as the width of the normal oscillation beam.

1 . A semiconductor laser device, comprising an external resonator configured by being provided with: a semiconductor laser which outputs a plurality of beams having different wavelengths; a combining optical system which spatially overlaps the plurality of beams output from the semiconductor laser; a wavelength dispersive element which overlaps the overlapped plurality of beams into a single beam by wavelength dispersion; and a partial reflecting mirror which reflects a portion of the single beam and returns same to the wavelength dispersive element,
 wherein when the width of the wavelength dispersive element in the beam overlapping direction in which the single beam is separated into a plurality of beams by wavelength dispersion is taken as a wavelength dispersive element width, and when the beam upon establishment of normal oscillation is taken as a normal oscillation beam, the wavelength dispersive element width is the same size as the width of the normal oscillation beam.   
     
     
         2 . The semiconductor laser device according to  claim 1 , wherein a plurality of the external resonators share the single partial reflecting mirror. 
     
     
         3 . The semiconductor laser device according to  claim 1 , wherein the wavelength dispersive element width is set in such a manner that the power of the beam irradiated onto the wavelength dispersive element is no less than 95% of the total power of the normal oscillation beam. 
     
     
         4 . The semiconductor laser device according to  claim 1 ,
 wherein the wavelength dispersive element width is set in such a manner that the power of the beam irradiated onto the wavelength dispersive element is no less than 95.0% and no more than 99.5% of the total power of the normal oscillation beam,   the semiconductor laser device further comprising: a beam sensor which is provided to the rear of the wavelength dispersive element and detects the power of the beam, from the normal oscillation beam, which is irradiated outside the wavelength dispersive element width and leaks to the rear of the wavelength dispersive element; and   a monitoring unit which monitors the state of the external resonator on the basis of a power value of the beam irradiated outside the wavelength dispersive element width as detected by the beam sensor.   
     
     
         5 . The semiconductor laser device according to  claim 2 , wherein the wavelength dispersive element width is set in such a manner that the power of the beam irradiated onto the wavelength dispersive element is no less than 95% of the total power of the normal oscillation beam. 
     
     
         6 . The semiconductor laser device according to  claim 2 ,
 wherein the wavelength dispersive element width is set in such a manner that the power of the beam irradiated onto the wavelength dispersive element is no less than 95.0% and no more than 99.5% of the total power of the nominal oscillation beam,   the semiconductor laser device further comprising: a beam sensor which is provided to the rear of the wavelength dispersive element and detects the power of the beam, from the normal oscillation beam, which is irradiated outside the wavelength dispersive element width and leaks to the rear of the wavelength dispersive element; and   a monitoring unit which monitors the state of the external resonator on the basis of a power value of the beam irradiated outside the wavelength dispersive element width as detected by the beam sensor.